Panasonic KX-TEB308UA / KX-TE82460X / KX-TE82493X / KX-A227X Service Manual ▷ View online
11.3. CROSS POINT SWITCH CIRCUIT
11.3.1. Composition
The cross point circuit composed of three cross point switch IC´s (IC601:8X16, IC602 and IC603:4X8).
1) Cross Point Switch IC Operation
1) Cross Point Switch IC Operation
The cross point SW (IC601) contains a 8X16 array of cross point switches along with a 7 to 128 line decoder and latch circuits.
Any one of the 128 switches can be addressed by selecting appropriate seven address bits. The selected switch can be turned
on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded for
matrix expansion.
The cross point SW´s (IC602, IC603) contain 4X8 array of cross point switches along with a 5 to 32 line decoder and latch
circuits. Any one of the 32 switches can be addressed by selecting appropriate five address bits. The selected switch can be
turned on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded
for matrix expansion.
Any one of the 128 switches can be addressed by selecting appropriate seven address bits. The selected switch can be turned
on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded for
matrix expansion.
The cross point SW´s (IC602, IC603) contain 4X8 array of cross point switches along with a 5 to 32 line decoder and latch
circuits. Any one of the 32 switches can be addressed by selecting appropriate five address bits. The selected switch can be
turned on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded
for matrix expansion.
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TEB30
8UA
11.4. INTERCOM CIRCUIT
11.4.1. INTERCOM CIRCUIT
1) Composition
This is composed of the following circuits:
a) +15V power source for the extension telephones
b) Hook detect for SLT and pulse dialing detect
c) Bell ring trip section
a) +15V power source for the extension telephones
b) Hook detect for SLT and pulse dialing detect
c) Bell ring trip section
2) Circuit operation
a) Power supply to the telephone
With the telephone off hook, a DC loop is formed, and current is supplied to the telephone. This circuit is limited to about 30mA
by Q200, Q202, R202, R204 and Q201, Q203, R203, R205.
+27V
With the telephone off hook, a DC loop is formed, and current is supplied to the telephone. This circuit is limited to about 30mA
by Q200, Q202, R202, R204 and Q201, Q203, R203, R205.
+27V
→R204→R202→Q200→RL201→telephone→RL201→Q201→R203→R205→AG
b) Hook detect for SLT and pulse dialing detect
When the telephone handset is taken off, DC loop is formed and the collector of U200 3,6 pin change to L from H.
And IC7 detects the off hook condition.
When the handset is replaced back on hook, the DC loop is interrupted and collector of U200 3,6 pin change to H from L and
EXT Pulse dialing is input either in the on hook or off hook condition, and the break number (on hook condition) is counted and
read as the dial number.
c) Bell ringing trip section
When the telephone is a signal line telephone, extension calling is executed by means of a ringing signal. When the ringing
signal is supplied, RL201 turns ON and the current flows are as follows:
Bell generation circuit
When the telephone handset is taken off, DC loop is formed and the collector of U200 3,6 pin change to L from H.
And IC7 detects the off hook condition.
When the handset is replaced back on hook, the DC loop is interrupted and collector of U200 3,6 pin change to H from L and
EXT Pulse dialing is input either in the on hook or off hook condition, and the break number (on hook condition) is counted and
read as the dial number.
c) Bell ringing trip section
When the telephone is a signal line telephone, extension calling is executed by means of a ringing signal. When the ringing
signal is supplied, RL201 turns ON and the current flows are as follows:
Bell generation circuit
→ ringing signal line → RL201 → telephone → R206 → AG → Bell generation circuit
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11.5. POWER FAILURE THROUGH CALL SWITCHING CIRCUIT
11.5.1. Circuit operation
If an AC power failure lasts longer than one second (momentary power failure), the COL is directly connected to the extension.
The COL1 will be connected with EXT101.
The COL1 will be connected with EXT101.
11.6. DATA COMMUNICATION CIRCUIT
11.6.1. Composition
This circuit is composed of the ASIC and the data communication interface circuits for the ICM circuit.
11.6.2. Circuit Operation
1) Data Communication of CPU (IC700)
The APT i/f module is built into CPU.
An RX/TX couple signal is shared by eight APT communications; this communicates via the selection signal.
That is, in the APT i/f module, extension 1- 4 port switch the port communicates every 4ms respectively with
#101
An RX/TX couple signal is shared by eight APT communications; this communicates via the selection signal.
That is, in the APT i/f module, extension 1- 4 port switch the port communicates every 4ms respectively with
#101
→#102→#103→#104..... →#101.....
When the extension is not connected with APT, it is recognized as an SLT connection and the dummy communication is
established.
established.
Interface block diagram of CPU and ICM
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KX-TEB308UA
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